Commit 14c4ad12 authored by Serge Semin's avatar Serge Semin Committed by Bjorn Helgaas
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PCI: dwc: Log link speed and width if it comes up 

Printing just "link up" isn't very informative for PCI Express. Even if the
link is up, bus performance can degrade to slower speeds or to narrower
width than both Root Port and its partner is capable of. In that case it
would be handy to know the link specifications as early as possible.

If the link comes up, log the link speed (PCIe generation) and width.

Link: https://lore.kernel.org/r/20220624143947.8991-2-Sergey.Semin@baikalelectronics.ru


Signed-off-by: default avatarSerge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Reviewed-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
parent 7659806a

drivers/pci/controller/dwc/pcie-designware.c

+16 −6
Original line number Diff line number Diff line
@@ -524,21 +524,31 @@ void dw_pcie_disable_atu(struct dw_pcie *pci, int index, 


int dw_pcie_wait_for_link(struct dw_pcie *pci)

{

	u32 offset, val;

	int retries;



	/* Check if the link is up or not */

	for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) {

		if (dw_pcie_link_up(pci)) {

			dev_info(pci->dev, "Link up\n");

			return 0;

		}

		if (dw_pcie_link_up(pci))

			break;



		usleep_range(LINK_WAIT_USLEEP_MIN, LINK_WAIT_USLEEP_MAX);

	}



	dev_info(pci->dev, "Phy link never came up\n");



	if (retries >= LINK_WAIT_MAX_RETRIES) {

		dev_err(pci->dev, "Phy link never came up\n");

		return -ETIMEDOUT;

	}



	offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);

	val = dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKSTA);



	dev_info(pci->dev, "PCIe Gen.%u x%u link up\n",

		 FIELD_GET(PCI_EXP_LNKSTA_CLS, val),

		 FIELD_GET(PCI_EXP_LNKSTA_NLW, val));



	return 0;

}

EXPORT_SYMBOL_GPL(dw_pcie_wait_for_link);



int dw_pcie_link_up(struct dw_pcie *pci)